81968

Appears in sequences

• Second member of Diophantine pair (m,k) that satisfies 6*(m^2 + m) = k^2 + k: a(n) = k.at n=10A077291
• Diagonal sums of number triangle A172380.at n=12A172382
• Numbers k with property that there is an m = m(k) such that m(m+1)/2 divides k(k+1)/2 and m(k) > m(i) for all i < k.at n=28A309423